Chris Kirk sunk an 18-foot putt for eagle on his final hole for a nine-under par 63 and a one-shot lead in the RSM Classic.
Kirk played the par 5s on the Plantation Course at Sea Island Golf Club in five under on Thursday.
Playing on the Seaside Course, Greg Chalmers ended the first round as the best-placed Australian with a two-under par 68 to be in a tie for 50th.
The seven lowest scores of the opening round came on the Plantation Course during a picturesque afternoon on the Golden Isles.
Joel Dahmen had a 64, while the group at 65 included Sea Island resident Hudson Swafford, Jason Kokrak and Brian Gay.
Nick Watney and Brice Garnett each had a five-under 65 on the Seaside Course, which will be used for the final two rounds.
Kirk won at Sea Island four years ago for the second of his four PGA Tour victories.
The RSM Classic is the final PGA Tour event of the calendar year.
